1. Field of the General Inventive Concept
Apparatuses and methods consistent with the exemplary embodiments relate to an image forming apparatus and a power transmission unit usable with the same, and more particularly, to an image forming apparatus with color registration improved by correcting an eccentricity error of a power transmitting gear, and a power transmission unit usable with the same.
2. Description of the Related Art
In general, an image forming apparatus is an apparatus to print an image on a printing medium based on an input image signal. The image forming apparatus may be classified into a printer, a copier, a facsimile machine, a multifunction printer with integration of these functions, and others known in the art depending on its function and may be classified into an inkjet type, a thermal transfer type, an electro-photography type, and others known in the art depending on its printing type.
Among them, the electro-photography type image forming apparatus is an apparatus to print an image on a printing medium by scanning an image receptor charged by a predetermined potential with light to form a latent image thereon, developing the latent image with toner of a predetermined color, and transferring and fixing the developed latent image onto the printing medium. This electro-photography type image forming apparatus may be also classified into a mono type or a color type depending on its color representation capability.
An electro-photography type color image forming apparatus includes a plurality of developing units corresponding to different colors, for example, yellow, magenta, cyan and black to implement a full color image by superimposing images formed by the respective developing units. The implementation of full color requires a color registration to allow respective color images developed by the respective developing units to be matched in place. Unfortunately, such an electro-photography type color image forming apparatus may have a color misregistration which may be caused by complex factors. Among these complex factors, a main mechanical factor for color misregistration is an eccentricity error between gears of a power transmission unit which transmits power between a driving source and an image receptor. Such an eccentricity error may be attributed to a mechanical tolerance in gear manufacture, which may occur from a difference between outer diameters of gears, with the difference being more than several tens of microns with respect to a predetermined reference value.